I have a very strange issue with my RT31P2. It's a little involved and I want to be thorough with my description, so I apologize in advance for the length of this post.

The symptom is basically that any IP sessions that are initiated from within my home network are fine, but sessions initiated outside, don't work right. This is NOT a simple port forwarding issue - the sessions will often connect, but then fail.

A good example is Remote Desktop Sharing with Windows XP. From home, I can connect to my work machine and run as long as I want, with no problems. From work, I can't - it will sometimes act like it's connecting, but then it will fail. Port 3389 is being forwarded to the right IP.

Everything else is the same way. I can browse the internet fine, but nobody can connect to my web server reliably - maybe half of the home page will load, taking 90 seconds or so, and then it will give an error. My email server sends email fine and from home I can connect to the POP3 server, but nobody can send me mail, and I can't connect to POP3 from work. Again, all the right ports are being forwarded.

In fact, if I enable Remote Management on the RT31P2, I can't use the the management interface from work. It will start to load, and I'll get maybe the first menu bar, but then it will time out. Every once in a while I will get the whole management screen, but if I try to save any changes or switch screens, it will fail.

At the moment, the RT31P2 is the only router on my network, but I also have a Linksys BEFSR41 router and a Linksys BEFW11S4 wireless router. If I replace the RT31P2 with either of the other two boxes, everything works fine. I can also plug the RT31P2 in behind one of the other two boxes and get the phone to work, but of course then it's not prioritizing voice traffic.

I'm pretty familiar with networking and Linksys products, and I've tried about everything I can think of. I've even cloned the MAC from one of the other boxes so I get the same dynamic IP from my ISP (Roadrunner from Time Warner), in case there was something goofy going on with one of Roadrunner's subnets.

I should also add that I've been running the Motorola box for about 6 months but it would only work behind one of the Linksys routers (I could never get it to forward all the ports I needed or act as a DMZ when it was in front of the router). I wanted to utilize voice QoS because I occasionally get garbled voice if I'm also doing something else bandwidth-intensive, so Vonage switched it out and sent the RT31P2.

I do exactly what you're wanting to do, and I did it with the RT31P2 with no problems. I was using Remote Desktop, running HTTP and FTP servers, even logging into OWA on an Exchange 2003 server.

I ended up getting a Linksys WRT54G wireless-g router, though, and putting the RT31P2 behind it. I too wanted QoS, but the RT31P2 does a horrible job at it, and it slowed down all of my traffic, even when I wasn't on the phone. The WRT54G has the most advanced QoS I've ever heard of on a $50 router, especially when you add third-party Sveasoft firmware. So if you can't get your woes straightened out, you may try going that route. I did it anyway, and I wasn't having nearly the problems that you've had.

After many hours to both Linksys and Vonage tech support, I stumbled on http://www.vonage-forum.com/ftopic3584.html , and it's exactly the problem. I can use Port Range Forwarding fine; UPnP is broke. (Do you successfully use UPnP Forwarding?) For the record, I have the 1.27.01 firmware on the RT31P2.

I haven't totally decided, but I'm leaning towards sending the RT31P2 back and keeping my old MOT VT1005. Either way, I'm going to put it behind a WRT54G.